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Retul Fit – Maximizing each pedal stroke

Retul Fit The bike is readjusted. In this case the stem is lowered and saddle moved forward.[/caption]

You’ve spent thousands on a bike and naturally you want to get the most out of your machine. Your goal might be to be a racer or an enthusiast, but regardless there is a common thread that both share when it comes to a bike frame – getting the correct fit to eliminate pain and improve your own biomechanics.

There are many types of bike fitting systems, some are based in science and others based on the fitter’s experience. The Retül fit uses motion-capture video and trained fitters to produce a fit that is based on biomechanics by evaluating your three planes of movement. To arrive at a fit the Retül system uses multiple video cameras and a computer program which creates a 3-D spatial model of your fit. This eliminates any of the fitter’s biases and creates an accurate to a millimeter fit that can be transferred to an already purchased bike or used to help with the geometry of a custom frame.

Before my fit began, certified Retül fitter Jim Cunningham, owner of the Greenville Cycling Center located at The Edge near downtown Greenville, tested me for any physical limitations I might have by leading me through a few simple stretches and holding a plank position, as well as evaluating my upper body strength by having me complete push-ups. From there he measured my legs and arms, noting any differences.

Next was my position on the bike. Previously I’d been fit using the Specialized Body Geometry system. However, that was eight years ago and much had changed. For the past couple of years I’ve switched bikes several times amd I had been suffering with lower back/hip pain which was due in part to my career combined with the march of time. By focusing on strengthening my core the back/hip pain has mostly been eliminated. As a result I knew my fit needed to be reviewed.

In order to track my movements on the bike, round LED markers were stuck to my shoe, arms, legs at critical points at the crest of my hip and knee. This enabled the video capture system to track my body’s movement as I pedaled. Typically fits are done when the rider is static. Retül measures the rider in motion, creating a more accurate measurement.

After a steady effort of pedaling my bike on a wind trainer, Cunningham looked at the computerized representation and was able to evaluate what, if any, changes needed to be made.

At the top of my pedal stroke the Retül program noted that my knee moved in and out. Ideally the leg should move up and down like a piston. With the wobble I wasn’t firing on all cylinders.

Jim added a wedge under my insole to reduce the wobble. Also he lowering my saddle five millimeters and pushing it forward 20 millimeters. Both of these changes were to improve my power by opening up the angles in my hip.

According to Retül the power of your pedal stroke is from about the top of pedal stroke (12 o’clock) to almost the bottom (5 o’clock). On the upstroke Jim says, “Basically the leg needs to get out of the way.” So unweight the leg on the up-stroke to conserve energy as the other leg powers over the top of the pedal stroke repeating the process.

Finally my cleat position was evaluated, which I knew was sorely needed. I have had many different shoes over the years and my cleat position had slightly changed with each new shoe. My cleat position was off, which wasn’t a surprise. My cleat position was altered to a position that would improve my pedal stroke.

All of these measurements are entered into a document which is given to the client and kept in a data base for future reference.

Obviously with most of my contact points changed I knew I would feel different on the bike. One concern I had was that my new lower saddle position would not allow me to generate the same power. While it did feel changed, nothing felt extreme. In fact after a few miles the pedal stroke felt more relaxed – it didn’t feel like I was forcing my leg to complete the full rotation of the pedal stroke. The new saddle height and changed fore/aft position actually felt smoother when compared to my old set-up.

Initially I intended to take a easy ride on the bike path before really testing the new position. But ego got the better of me, so I rode to Paris Mountain – a 2.2 mile climb which is a common testing ground for all cyclists in the Upstate area.

Keeping a steady tempo, aiming to ride at threshold, I came just five seconds shy of beating my best time to the summit – an effort done at over threshold. In repeated tests, again riding at threshold for repeatability, I slightly improved that time again. I feel confident that if I was aiming to beat my record to the top I could. As I have continued to ride with the Retül fit I’ve noticed feeling smoother on the bike and not riding with some minor discomfort that we take for granted as a cyclist.

You’ve spent the money on the bike and even invested in the newest aerodynamic widget. The better investment is a good fit that enables you to get the most out of your bike and yourself.

A certified Retül fit is available at the Greenville Cycling Center.

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